1. Field of the Invention
The present invention relates to filtering of generally broadcast messages which are processed based on the applicability of the message to the receiver of the message and, more particularly, to a system which provides such filtering based on the past movement history of a movable receiver so as to alert the receiver to, for example, potentially dangerous situations to which the receiver may have been exposed.
2. Related Art
As discussed in commonly assigned U.S. Pat. No. 5,636,245, to Ernst et al, region-specific information is, in general, disseminated by predetermined point-to-point communication or by a general broadcast which must be manually monitored in order to extract information peculiar to a position, velocity and time of interest. For example, marine weather data is continuously broadcast and mariners must monitor the broadcast for long periods of time in order to obtain the information peculiar to their region. Even then, the exact region affected may require computation or may be ambiguously defined. There is also the possibility that the user may miss information of interest because he or she occupies an unknown location, is unfamiliar with the region, or uses a different frame of reference, among other reasons.
Another example is tactical ballistic missile (TBM) warning, which is derived from space and ground based sensor data, and is provided through a variety of broadcast and general purpose communications systems to a small subset of in-theater forces. Currently, such warning requires transportable processing stations that can generate information about specific situations in the field but cannot directly communicate with all individuals affected. The timeliness, reliability, and dispersion of information under these conditions are of concern. Because warning is in the form of geographical coordinates and time of predicted impact, users must interpret the data to determine if the warning affects them.
Some current commercial systems are using Global Positioning System (GPS) information to select relevant data from computer based files such as appropriate electronically stored maps for use in automobiles. These are useful for relatively static information but fail to address dynamic environmental or combat factors.
U.S. Pat. No. 5,243,652 to Teare et al discloses a database access system in which each mobile user has a positioning system which transmits position information to a central facility. This central facility then grants or denies database access depending on the geographical location of the mobile user.
U.S. Pat. No. 4,860,352 to Laurance et al discloses a system in which a satellite system determines the position of a transmitter at a first location and a receiver at a second location. The transmitter position is appended to the received message which is sent by the satellite system to the receiver. The receiver receives the appended message, extracts the transmitter position data and compares the extracted transmitter position with a stored transmitter position. If the positions correlate, the receiver knows it has received an authentic message.
The above-mentioned U.S. Pat. No. 5,636,245 concerns an improvement over these prior art systems and discloses a filtering system which determines whether generally broadcast information is relevant to a particular user based on the location, velocity and/or time of an object or event of interest. The system includes a general broadcasting unit comprising a transmitter for broadcasting messages including an information segment comprising a region, velocity and/or a time corresponding to an event. A remote unit includes a receiver for receiving the broadcast messages and storage means for storing spatial position information relating to the remote unit and/or a further remote region of interest to the remote unit, as well as storing data selection information. The stored data selection information is related to information contained in the broadcast segment and is compared with the latter in the matching processor and used, along with spatial position information, to determine whether a match condition is satisfied. If so, the message is disseminated, e.g., an alarm is sounded and the message is displayed.
A number of patents of potential relevance have issued subsequent to U.S. Pat. No. 5,636,245, including the following: U.S. Pat. Nos. 6,028,514 and 6,084,510 to Lemelson et al; U.S. Pat. No. 6,111,521 to Mulder et al; U.S. Pat. No. 5,635,924 to Tran et al; U.S. Pat. No. 5,898,680 to Johnstone et al; U.S. Pat. No. 6,159,894 to McCormick et al and U.S. Pat. No. 5,764,657 to Jones.
In accordance with the invention, a discriminating or filtering system is provided which addresses an important problem that is not addressed by the prior art, including the various patents discussed above. More specifically, the prior art is concerned with the present effect of events or, in some instances, with the predicted effect of future events. However, there are a number of situations wherein the past effect of an event is important. For example, where there has been a spill or other release of a toxic chemical or the deployment of a biological weapon such as a poisonous gas, it is important to know not only if a movable remote unit is located in a region of danger or is heading for such a region, but also if the unit has been in that region at any time during the travel history of the unit. In this regard, although the remote unit may be out of danger now and heading away from danger, the remote unit may have been unknowingly exposed to the toxic threat at a previous time during the travel of the unit. This determination may also be complicated by the fact that the threat itself has moved or spread from its initial site, i.e., toxic fallout or noxious gases may have spread, so that the time and location of the original release and the rate (velocity) of the spread must be taken into consideration in determining whether there has been harmful exposure.
In accordance with one aspect of the invention, a message filtering system is provided for filtering generally broadcast messages received by a movable unit, said system comprising a receiver for receiving a generally broadcast message including an information segment comprising at least one of a location, a velocity and a time relating to an event of potential interest to the movable unit which has occurred in the past and which has continuing consequences for the movable unit; spatial position input means for inputting spatial position information relating to said remote unit during the movement of the remote unit; storing means for storing said spatial position information so that a history is provided of the movement of the remote unit and for storing data selection information related to information contained in said information segment of the generally broadcast message used in determining whether, based on the information contained in said information segment and the stored history of movement of the movable unit, the broadcast message is of interest to the movable unit; a matching processor connected to said storing means and to said receiver for comparing said information segment with said data selection information and said history of movement of the movable unit to determine whether a match condition is satisfied and for, when a match condition is satisfied, outputting a match signal; and disseminating means for, responsive to receiving said match signal, processing and disseminating said broadcast message.
In situations wherein the information segment of the broadcast message contains time-location information relating to both the time of the event and the location of the event, the matching processor preferably compares said time-location information with said stored history of movement of the unit and said stored data selection information.
In situations wherein the event is a toxic event having toxic effects that spread from the original location of the event and the information segment contains toxic event information relating to the time of the original event, original location of the event, the velocity of spread of the event, the matching processor compares said toxic event information with the stored history of movement of the unit and the stored data selection information.
In accordance with a further aspect of the invention, a communication system is provided which comprises a general broadcasting unit comprising: a message generating means for generating a generated message related to detection of a toxic event occurring in the past and having continuing consequences; a segment generating means for generating an information segment comprising at least one of a region, a velocity and a time relating the event, and for incorporating said information segment into said generated message to produce an outputted message, and a transmitter for broadcasting said outputted message; and a movable remote unit comprising: a receiver for receiving said outputted message from said transmitter of said general broadcasting unit; spatial position input means for inputting spatial position information relating to said remote unit during movement of the remote unit; a storing means for storing said spatial position information so that a history is provided of the movement of the remote unit and for storing data selection information related to information contained in said information segment used in determining whether because of any one of the region of the event, the velocity of toxic effects associated with the event and the time of the event, the event has posed a threat to the remote unit by virtue of exposure of the remote unit to said toxic effects during the history of the movement of the remote unit; a matching processor connected to said storing means and to said receiver for comparing said information segment in said outputted message with said spatial position information and said data selection information stored in said storing means to determine whether a match condition is satisfied, and for, when a match condition is satisfied, outputting a match signal, and a disseminating means for, responsive to receiving said match signal, processing and disseminating said message in accordance with said match signal.
Other features and advantages of the invention will be set forth in, or will be apparent from, the detailed description of the preferred embodiments which follows.